Main Menu

Secondary Menu

Author Options:

Can someone help me? My electromagnet wont work ):< Answered

Hello! i'm kinda new to instructables, so plz don't get mad if i post something wrong... Anyway, my magnet is misbehaving. It just doesn't wanna move anything at all. That first image up there is my electromagnet :D (sry for the low resolution, my camera is more than capable of HD, I don't know why its blurry)

How i have it powered is i'm running it off of a 5 volt AC charger. I know, I know. AC wont work for electromagnets. Well, that second picture that i got up there is a set of 4 diodes that makes the AC power turn to DC. I've got both ends of the DC power going to both ends of my magnets.

Then I turn it on, and was disappointed to see that my magnet didn't like the way i made it and decided not to work. I've also got the wire insulated and an iron core, and am also trying to pick up iron nails, but to no success. not even a budge! Sry if i'm making this long... i'm just trying to give you all the information I can ;D

You don't have a lot of turns, you will need to push lots of amps through those few turns to get a strong magnet. Also, you may have damaged the insulation of the magnet wire, causing it to short directly to the screwdriver.

That few turns of wire has very little resistance (it looks like a short circuit) and those wimpy diodes aren't going to do the business. Probably 1 amp maximum. I think you killed the diodes. If you want to use that few turns and no current limiting device, then you need these diodes:

By the way, it is possible to drive an electromagnet with alternating current (AC), so I don't follow what you mean by saying, "AC wont work for electromagnets." There is such a thing as an AC electromagnet.

If you have approximately 11 minutes to spare, I found this short film at archive.org. It's kind of old. Dang Roman numerals! What is MCMLXI in decimal? 1961, I think.

> Are you sure that wire is insulated? It looks like bare metal to me - you have to insulate each turn from the next, as well as from the core.

> The core isn't the best choice of material - non-rusty iron or steel will magnetise more efficiently.

> Move the coil to the pointy end of the screw driver - moving the pole to the end of the core concentrates the field lines more effectively.

> Is your power supply working? A coil like yours is really just a long short (?) in the circuit, so you may have tripped fuses, popped circuit breakers or melted something delicate inside the power supply.

> Have you got your diodes the right way round? Google for "rectifier circuits" to check.

> Have the diodes burnt out?

> Even with a rectified supply, the current is going to be switching on and off very rapidly, which will reduce the power of your electromagnet.

------

I would check your actual electromagnet is working by using an ordinary battery pack - connect a reliable, DC supply, just to check something happens.

If the e-mag works with batteries, then the power supply is your issue. If it doesn't work with batteries, then the e-mag is the issue, see my first three points above.

If you don't have any sort of testing equipment, you can check your diodes are working if you remove them from the circuit - can you feel a faint buzz when you rest your e-mag against a nail? That's the power switching at 50-60Hz.

Using nails to test your magnet has major resolution/precision issues. Will it pick up paperclips? Pins? Iron filings? Will it make a compass needle twitch when you connect or disconnect the power?

-------

Don't be discouraged, we all learn more from mistakes than from success without effort. You may reach the point of needing to discard everything in your photos and starting again from scratch, but you will eventually learn how to make an effective, useful electromagnet.